In the process of plastic extrusion, raw plastic is fed into a heated extruder cavity or cylinder. Inside the machine, the plastic beads and any accompanying material move through an opening in the extruder cavity towards a screw mechanism. Extrusion refers to the Manufacturing process in which a softened blank of a metal or plastic material is forced through a shaped metal piece or die to produce a continuous ribbon of the formed product. Materials such as polystyrene, nylon, polypropylene and polythene can be used in a process called extrusion.
The manufacturing process in which plastic is melted to shape it and cut out the length is called plastic extrusion. There are variations to the extrusion process depending upon what type of extrusion is being performed. Here is a look at the different types of extrusion, and the differences from the basic process for each. Types of Plastic Extrusion are sheet extrusion, blown film extrusion, tubing extrusion.
The moulding process is one of the most important plastic processing operations. Plastic moulding especially thermoplastic items may be produced by compression moulding methods, but since they are soft at the temperature involved, it is necessary to cool down the mould before they may be ejected. Injection moulding is a manufacturing process for producing parts by injecting material into a mold. using photopolymers which do not melt during the injection moulding of some lower temperature thermoplastics, can be used for some simple injection moulds. Injection molding can be performed with a host of materials, including metals, glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers.
The amount of plastic consumption per capita, as per statistics, is steadily on the rise and is expected to touch a value that is 2.5 times the growth in GDP. At present, only 10-15 per cent of the plastic processing units can be classified as medium scale operations while the rest operate on a small-scale basis. India’s burgeoning middleclass is driving the demand for plastic and plastic products and today the sector is one of the fastest growing in the Indian economy. In terms of polymers, India is a small country, consuming only 4 kilograms per capita, but things are changing. Going forward, India is poised to be one of the top five polymer consumers worldwide by the end of the decade. In order to compete with the best in the world, India needs to acquire better technology on the processing side. At present extrusion process accounts for nearly 70 percent of plastics processing, while injection and blow moulding account for 20 and 5 percent respectively.
The mould has its own importance, which give the required shapes of the products. The vast growth of injection moulding is reflected dramatically in many types and sizes of equipment available today. Metal injection molding (MIM) is experiencing a worldwide boom, with an estimated market worldwide of more than $1 billion per year, and compound annual growth rates estimated to be as high as 20 percent. Metal injection moulding (MIM) technology is used to form a near net-shape metal part by consolidating metal powder in a special sintering process.
FURTHER INFORMATION:
The Complete Technology Book on Plastic Extrusion, Moulding and Mould Designs describe detailed information on subject. The major contents of book are-preparation of plasma films, transport phenomena in polymer films, acrylic fabrication, reinforcements for thermosets, miscellaneous thermoplastic processes, compression and transfer molding, disciplined process strategy for injection moulding, injection molding, blow molding, extrusion, newly developed injection moulding technology, thin walled injection moulding, mold cooling best bet for high profits, mould materials and processing methods etc.
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